This invention relates to ice structures, and, more particularly, to means for increasing the vertical load bearing capacity of an ice sheet.
The depletion of relatively easy-to-reach oil and natural gas reserves and the remarkable increase in the worldwide value of oil and gas has brought about intensified exploration and production efforts in the harshly cold areas of the world such as the Arctic. This activity comprehends both onshore and offshore efforts, and the latter includes its own particularly difficult problems. The year-round use of conventional drillships or drilling platforms is precluded because of the tremendous forces exerted by the shifting ice which is universally present during at least a part of the year in these regions. Specially configured drillships and drilling platforms, as well as semi-submersible structures, have been constructed and/or proposed to deal with the problems associated with offshore operation in ice covered areas. Additionally, it has been proposed to employ the ice itself to support either drilling and production apparatus or logistics support buildings such as personnel housing, storage warehouses, storage tanks and the like.
One factor which has limited the direct use of the sheet ice to support such structures has been its limited and variable strength. Thus, those skilled in the art will appreciate that it would be highly desirable to provide means by which the load bearing strength of an ice sheet may be predictably and significantly augmented, and it is to this end that the present invention is directed.
It is therefore a broad object of this invention to provide means for increasing the load bearing strength of an ice sheet.
It is another object of this invention to provide such means by which the strength augmentation is effected predictably and in accordance with the load to be borne.
It is yet another object of this invention to provide such means which is relatively simple to incorporate into the load bearing system and which is reliable in operation.
In another aspect, it is an object of this invention to provide such means by which the use of a plurality of load strength augmentation units are used in coordination to accomodate varying loads across a large area of the ice sheet.